1. Field of the Invention
The present invention relates to an undocking method for a multilayer-dock structure constituted by docking a plurality of expansion units to a portable PC.
2. Description of Related Art
In recent years, portable personal computers (hereafter referred to as portable PCs) having various sizes and functions have been developed because mobile computing has been spread. For example, there is a notebook-type personal computer (PC), a sub-notebook-type PC, palm-top-type PC, and a PDA (personal data assistant; which may be translated as portable information terminal). The functions to be provided for the portable PC are limited. Therefore, when it is necessary to expand the functions, one or more expansion unit is or are connected to the portable PC. The expansion unit is referred to as a docking station or port replicator.
A portable PC and an expansion unit are electrically connected with each other through a connector and thereafter, logically connected with each other. This operation is referred to as docking. Even if a portable PC and an expansion unit are only electrically connected, the portable PC cannot operate the expansion unit. To make it possible for the portable PC to use the expansion unit, it is necessary for an operating system (OS) to recognize the expansion unit. This is logical recognition. Docking is not completed until the OS logically recognizes the expansion unit and the portable PC is ready to use the expansion unit.
Electrically and logically separating a portable PC from an expansion unit is referred to as undocking.
Published Unexamined Patent Application No. 8-6668 discloses an art capable of smoothly docking also in a power saving mode such as a mode in which a portable computer is powered on or suspended. The essential point of the disclosed contents will be described below. When all signals are mechanically and collectively connected, it is possible to immediately use a port signal which can be hot-plugged when the signals are connected. However, for a bus signal which cannot be hot-plugged, it is possible to keep an electrical separation state when the signals are connected. Thereby, even if a user erroneously attempts docking under operation, it is possible to prevent the hardware from breaking.
The number of expansion units to be docked to a portable PC is usually one. However, it is preferable to prepare two types of expansion units (a first expansion unit and a second expansion unit) and dock either of them to the portable PC. For example, a CD-ROM drive or audio system is provided for the first expansion unit. Moreover, I/O ports such as a video port, printer port, mouse port, keyboard port, PCI device, and LAN port are provided for the second expansion unit. Then, a double-layer-dock structure constituted by docking the portable PC and the first expansion unit or a triple-layer-dock structure constituted by docking the portable PC, first expansion unit, and second expansion unit is realized. Thus, the triple-layer-dock structure can be used as a PC equivalent to a desktop-type PC. Moreover, the double-layer-dock structure can be used as a PC having a function between the portable PC alone and the triple-layer-dock structure.
As described above, when the triple-layer-dock structure is realized by docking the first expansion unit and second expansion unit to the portable PC, it can be used as a PC equivalent to a desktop-type PC. Therefore, the facility is improved. However, when hot-undocking only a portable PC from a triple-layer-dock structure, a problem occurs. Hot-undocking represents separating a portable PC under normal operation state from a triple-layer-dock structure. In this case, the normal operation state is a state other than power-off, suspend, hibernation, and standby states and a state capable of operating the PC. The first and second expansion units have devices according to standards different from each other as resources. As a result, when hot-undocking only the portable PC from the triple-layer-dock structure, it is necessary to separately eject the resource of the first expansion unit and that of the second expansion unit. That is, it may not be possible to undock both the first and second expansion units at the same time through one-time undocking operation. Therefore, because it is necessary to perform the undocking operation two times, a problem occurs in that the operability is deteriorated.
The present invention relates to a method for undocking a structure having an optional number of tiers from a multilayer-dock structure constituted by docking a plurality of expansion units respectively having an intrinsic resource to a portable PC.
A target expansion unit located immediately below a structure to be undocked and serving as an expansion unit in the multilayer-dock structure generates an undock event. A controller provided for the portable PC and receiving the undock event issues a system management interrupt. The service program of a system receiving the system management interrupt requests an operating system to separate resources of the target expansion unit and its low-order expansion unit from the control by the operating system. The operating system performs the operation for separating the resources from its control. The service program electrically separates interfaces of the resources. In this case, the service program is allowed to have an optional configuration as a part of an application program, device driver, or operating system.
Because the present invention is configured as described above, it is possible to unitedly obtain an object to be undocked through vision and operation and thereby, improve the operability.